Polyunsaturated fatty acids (PUFAs) are often present in sizable amounts in high oleic oils and high oleic oil derivatives that are used in foodstuffs and as oleochemicals in industrial and material applications. Many of these oils are obtained from plants and plant seeds, where PUFAs serve as important metabolic compounds necessary for growth and survival. The table below shows the approximate fatty acid content of major commercial vegetable oils having a high oleic acid variety.
OilC18:1PUFAsSoybean Oil30%60%High Oleic Soybean Oil75%13%Canola Oil60%35%High Oleic Canola Oil70%15%Mid Oleic Sunflower Oil65%25%High Oleic Sunflower Oil80%10%Safflower Oil15%75%High Oleic Safflower Oil75%15%
Soybean, canola, and safflower oils show considerable amounts of PUFAs, and their high oleic versions still show appreciable amounts of PUFAs. Purification of the oils to remove the PUFAs is difficult and costly and thus not feasible on a commercial scale.
Unlike oleic acid which contains a single double bond, PUFAs contain more than one double bond in a fatty acid chain. This increase in unsaturation causes the PUFAs to be susceptible to autoxidation, polymerization, and other chemical reactions. Particularly when exposed to heat, light, and oxidative conditions, the increased reactivity of the PUFAs leads to unwanted side products that contaminate the oil. In foodstuffs such side products can negatively affect taste and smell. As oleochemicals in industrial and material applications, the side products can result in a decrease in the stability and desired performance characteristics of the oleochemical or material.